Preheat oven to 350˚F. Brush baking dish with 1 tablespoon melted butter until well coated, set aside.
For caramel sauce: Pour butter, sugars, water, and salt into a medium saucepan and stir together over medium heat.
Allow mixture to boil for about 5 to 6 minutes, stirring frequently (the longer you boil this, the thicker your caramel sauce will be).
Remove from heat and carefully stir in the heavy cream and vanilla (mixture will bubble up, be careful!) Set aside and cool until ready to use.
For bread pudding: Place croissant cubes, apples and ½ cup sugar into a large mixing bowl, set aside.
In another mixing bowl combine remaining sugar, milk, cream, eggs, remaining butter, vanilla extract, cardamom, and cinnamon and whisk together until light and fluffy.
Pour egg mixture over croissant and apple mixture and toss together until well coated.
Pour mixture into the prepared baking dish and allow mixture to sit for about 15 minutes.
Bake bread pudding in the oven for 30 to 35 minutes or until a knife comes out clean when inserted into the center and the top is golden brown.
Remove from oven and drizzle with 1 cup of caramel sauce. Allow bread pudding to cool, about 10 minutes.
Serve with extra caramel sauce.